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I have reset the password on a Cisco 1700 router, now when I copy run start or write mem then reload or reboot, it defaults to factory settings, i.e. it is not holding the configuration I have just written.

To reset the password I used the boot from ROMmon command.

Any help would be very much appreciated.

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  • Have you tried to show startup-config after you reboot your router?? If you see you configuration there. Your configuration register is on 0x2142 or ignore nvram. Change it to 0x2102 to boot normally – user63784 Dec 9 '19 at 17:51
  • Hi Guntbert, Thank you for your comments, Andrey sorted me out on the previous answer but thank you anyway. – Andy Mac Dec 10 '19 at 18:49
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Check your config register running show version. If it shows 0x2142 then it means that on boot router ignores nvram config and loads factory default.

To change that, load router, in configuration mode enter config-register 0x2102. Write memory and reload.

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For completeness - Another possibility for a fairly old device like this is a flash failure, where a write "succeeds" but never actually writes.

You might find the same condition on a SD card that has been used a lot in a camera, or a dashcam or any kind of device that records and overwrites old files a lot.

If the flash is removable/replaceable then that's a decent fix. If the flash is soldered(sodded) to the board then you're up for replacing the flash chips. Or scour ebay for a repalcement device.

If this router is only used for labs, then even with non-permanent flash it can still perform as a useful learning tool. Just don't turn it off or reload it, and consider setting up something like rancid or oxidized to fetch its config periodically as a backup. But don't use such a device in prod without seriously considering your alternatives.

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    Actually, the router uses NVRAM, not flash, to hold the configuration. Routers can hold the OS, itself, on flash. NVRAM doesn't have the same problem that flash has. – Ron Maupin Nov 27 '19 at 0:32
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    Isn't "NVRAM" pretty much a generic term that includes flash among other things? – user1686 Nov 27 '19 at 20:45
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    @grawity, no. NVRAM is RAM (like computer memory) that can maintain it's state with a minimum of power input. Ever had a computer (or read about one) where the "BIOS battery" died and it had issues booting because BIOS lost its settings? That is a problem associated with the use of NVRAM. Flash is a form of ROM that has the ability to be rewritten. So while it needs no power to maintain it's state, it does begin to degrade the more it is rewritten. Actually, your comment would probably make a better question. You may consider posting it as such. – YLearn Nov 27 '19 at 22:17
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    @YLearn You're right on the NVRAM's actual meaning, but I've worked on routers and switches, and NVRAM is usually used as a generic term nowadays meaning "configuration partition" or sometimes even just "configuration file". On the routers I've worked on, there was no hardware NVRAM. This switch to NAND or NOR flashes is recent though, as the older flash drives were really slow compared to an NVRAM (the cost / benefit ratio is not as it used to be, the performance gain from an NVRAM is negligible especially compared to the read speed of a NOR flash). – John Hamilton Nov 28 '19 at 8:01
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    @JohnHamilton, please note I was resonding to grawity's comment of Isn't "NVRAM" pretty much a generic term that includes flash among other things? While some platforms still use the term NVRAM as a configuration partition on a flash medium for backwards compatibility and familiar usage, the term NVRAM has never been a generic term that included flash. However, yes on modern platforms if the term NVRAM is used, the reverse of that statement is often true, that flash includes NVRAM. – YLearn Nov 29 '19 at 6:42

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